1 Department of Neurology, Section Neuropsychology, RWTH Aachen, Germany 2 School of Psychological Sciences, Faculty of Medical and Human Sciences, University of Manchester, UK 3 SRH University of Applied Sciences, Gera, Germany 4 JARA-BRAIN, Aachen Juelich Research Alliance, Translational Brain Medicine, Germany
5 Department of Neurology, University Medical Centre Freiburg, Germany.
Brain. 2015 Apr;138(Pt 4):1097-112. doi: 10.1093/brain/awv022. Epub 2015 Feb 15.
Both hemispheres are engaged in recovery from word production deficits in aphasia. Lexical therapy has been shown to induce brain reorganization even in patients with chronic aphasia. However, the interplay of factors influencing reorganization patterns still remains unresolved. We were especially interested in the relation between lesion site, therapy-induced recovery, and beneficial reorganization patterns. Thus, we applied intensive lexical therapy, which was evaluated with functional magnetic resonance imaging, to 14 chronic patients with aphasic word retrieval deficits. In a group study, we aimed to illuminate brain reorganization of the naming network in comparison with healthy controls. Moreover, we intended to analyse the data with joint independent component analysis to relate lesion sites to therapy-induced brain reorganization, and to correlate resulting components with therapy gain. As a result, we found peri-lesional and contralateral activations basically overlapping with premorbid naming networks observed in healthy subjects. Reduced activation patterns for patients compared to controls before training comprised damaged left hemisphere language areas, right precentral and superior temporal gyrus, as well as left caudate and anterior cingulate cortex. There were decreasing activations of bilateral visuo-cognitive, articulatory, attention, and language areas due to therapy, with stronger decreases for patients in right middle temporal gyrus/superior temporal sulcus, bilateral precuneus as well as left anterior cingulate cortex and caudate. The joint independent component analysis revealed three components indexing lesion subtypes that were associated with patient-specific recovery patterns. Activation decreases (i) of an extended frontal lesion disconnecting language pathways occurred in left inferior frontal gyrus; (ii) of a small frontal lesion were found in bilateral inferior frontal gyrus; and (iii) of a large temporo-parietal lesion occurred in bilateral inferior frontal gyrus and contralateral superior temporal gyrus. All components revealed increases in prefrontal areas. One component was negatively correlated with therapy gain. Therapy was associated exclusively with activation decreases, which could mainly be attributed to higher processing efficiency within the naming network. In our joint independent component analysis, all three lesion patterns disclosed involved deactivation of left inferior frontal gyrus. Moreover, we found evidence for increased demands on control processes. As expected, we saw partly differential reorganization profiles depending on lesion patterns. There was no compensatory deactivation for the large left inferior frontal lesion, with its less advantageous outcome probably being related to its disconnection from crucial language processing pathways.
大脑的左右半球都参与到失语症患者的言语产生缺陷的恢复中。词汇治疗已被证明可以诱导大脑重组,即使在慢性失语症患者中也是如此。然而,影响重组模式的因素相互作用仍然没有得到解决。我们特别感兴趣的是病灶部位、治疗引起的恢复和有益的重组模式之间的关系。因此,我们应用了强化词汇治疗,并通过功能磁共振成像进行了评估,对 14 名有言语检索缺陷的慢性失语症患者进行了治疗。在一项组研究中,我们旨在阐明命名网络的大脑重组,并与健康对照组进行比较。此外,我们还打算通过联合独立成分分析将病灶部位与治疗引起的大脑重组相关联,并将由此产生的成分与治疗效果相关联。结果发现,在患者中,病灶周围和对侧的激活基本上与健康受试者的预发病理命名网络重叠。与对照组相比,训练前患者的激活模式减少,包括受损的左半球语言区、右中央前回和颞上回,以及左尾状核和前扣带回皮质。由于治疗,双侧视认知、发音、注意力和语言区的激活减少,而右颞中回/颞上回、双侧楔前叶以及左前扣带回皮质和尾状核的患者减少更为明显。联合独立成分分析揭示了三个成分,这些成分索引病变类型,与患者特定的恢复模式相关联。(i)连接语言通路的左侧额下回的扩展额部病变的激活减少;(ii)小的额部病变发生在双侧额下回;以及(iii)大的颞顶叶病变发生在双侧额下回和对侧颞上回。所有的成分都显示出前额叶区域的增加。一个成分与治疗效果呈负相关。治疗仅与激活减少有关,这主要归因于命名网络内的更高处理效率。在我们的联合独立成分分析中,所有三种病变模式都揭示了左侧额下回的去激活。此外,我们发现控制过程的需求增加。正如预期的那样,我们看到了取决于病变模式的部分不同的重组模式。对于左侧额下回的大病变,没有补偿性去激活,其不太有利的结果可能与其与关键语言处理通路的中断有关。
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